Permeant Fluorescent Probes Visualize the Activation of SARM1 and Uncover an Anti-neurodegenerative Drug Candidate

Li, W. H.; Huang, K.; Cai, Y.; Wang, Q. W.; Zhu, W. J.; Hou, Y. N.; Wang, S.; Cao, S.; Zhao, Z. Y.; Xie, X. J.; Du, Y.; Lee, C.; Lee, H. C.; Zhang, H.; Zhao, Y. J.

doi:10.1101/2021.02.24.432704

bioRxiv · 10.1101/2021.02.24.432704

Permeant Fluorescent Probes Visualize the Activation of SARM1 and Uncover an Anti-neurodegenerative Drug Candidate

Li, W. H.·Huang, K.·Cai, Y.·Wang, Q. W.·Zhu, W. J.·Hou, Y. N.·Wang, S.·Cao, S.·Zhao, Z. Y.·Xie, X. J.·Du, Y.·Lee, C.·Lee, H. C.·Zhang, H.·Zhao, Y. J.

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Abstract

SARM1 regulates axonal degeneration through its NAD-metabolizing activity and is a drug target for neurodegenerative disorders. We designed and synthesized fluorescent conjugates of styryl derivative with pyridine to serve as substrates of SARM1, which exhibited large red-shifts after conversion. With the conjugates, SARM1 activation was visualized in live cells following elevation of endogenous NMN or treatment with a cell-permeant NMN-analog. In neurons, imaging documented SARM1 activation preceded vincristine-induced axonal degeneration by hours. Library screening identified a derivative of nisoldipine as a covalent inhibitor of SARM1 that reacted with Cys311 in its Armadillo-domain and blocked its NMN-activation, protecting axons from degeneration. CryoEM showed that SARM1 was locked into an inactive conformation by the inhibitor, uncovering an unsuspected neuroprotective mechanism of dihydropyridines.

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Li, W. H., Huang, K., Cai, Y., Wang, Q. W., Zhu, W. J., Hou, Y. N., Wang, S., Cao, S., Zhao, Z. Y., Xie, X. J., Du, Y., Lee, C., Lee, H. C., Zhang, H., Zhao, Y. J.. 2021-02-25. Permeant Fluorescent Probes Visualize the Activation of SARM1 and Uncover an Anti-neurodegenerative Drug Candidate. https://doi.org/10.1101/2021.02.24.432704

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